Method of making universal joints



Dec. 12, 1961 G. B. STILLWAGON, JR

METHOD OF MAKING UNIVERSAL JOINTS Original Filed May 5, 1955 l", @MAQ fv- Hwa/fw United States Patent 3,912,315 Patented Dec. 12, 1961 Free3,012,315 METHOD OF MAKEIG UNIVERSAL JOINTS George B`. Stillwagon, Jr.,546V Hathaway Road, Dayton,

Ohio, assignor of one-half to Kenneth G. Fraser, Dayton, Ohio Originalapplication May 5, 1955, Ser. No. 506,127, now Patent No. 2,896,431,dated July 28, 1959. Divided and this application Mar. 21, 1958, Ser.No. 722,931

4 Claims. (Cl. 29--423) This invention relates to a universal joint andmethod of making same, and more particularly to a universal jointwherein a portion of the joint is elastomeric material.

The present application is a division of my copending application SerialNo. 506,127, tiled May 5, 1955, entitled Universal Joint and Method ofMaking Same, now Patent No. 2,896,431, issued July 28, 1959.

The invention has for its object the provision of a more simplyconstructed universal joint, made of a minimum number of parts, and istherefore more simple and more efficient in operation. A further objectof the invention is the provision of a universal joint in which aportion of the joint is made of vulcauizable material which is moldedinto the joint in the process of assembling the parts, and issubsequently vulcanized.

A further object of the invention is the provision of a method of makinga bonded universal joint wherein an interstice or groove is formed in anelastomeric bonding element during the vulcanizing process by means of alow temperature melting insert which is removed.

A further object of the invention is the use of a process which makespossible universal exibility in the joint without sacrificing strengthand durability.

Other objects and advantages reside in the construction of parts, thecombination thereof, the method of manufacture, and the mode ofoperation, as will become more apparent from the Vfollowing description;

Referring to the drawing,

FIGURE l is a cross section of the universal joint in one state in itsmanufacture, showing the parts assembled ready for vulcanizing.

FIGURE 2 is a cross sectional view showing the joint after vulcanizing,with a temporary supporting pin removed.

FIGURE 3 shows the universal joint completed, after the pin has beenwithdrawn and the material of an insert has -been melted out.

FIGURE 4 is a perspective view of the completed universal joint.

FIGURE 5 is a cross sectional view of a modied form of the universaljoint.

Referring more in detail to the drawing, the completed universal jointconsists of a pair of coupling members and 12 having beveled adjacentend surfaces 14 and 16 respectively, and an elastomeric bonding element18 provided with annular depressed curved surfaces 20 and 22 and acentrally located inwardly directed annular groove or circular cavity24, and a metallic sleeve 26 surrounding the bonding element.

The formation of the elastomeric member 18 is such as to allow freeuniversal movement. A pair of annular concave surfaces 20 and 22 aremolded into the opposite exposed surfaces surrounding the couplingmembers. The internally directed annular cavity 24 contributes to thisexibility, as do also Ithe beveled adjacent ends of the couplingmembers. The joint completed and ready for use is shown in FIGURE 3.

The steps in the manufacture of the universal joint are as follows: Ametal pin 28 is provided with an annular reduced portion or recess 30.The diameter of the pin 28 is such as to tit snugly into each of thecoupling members 10 and 12. A metal washer 32 is cast on the pin 2Siitting into the annular recess 30. The diameter of the washer 28 islarger than the exterior diameter of the coupling members 10 and 12, andof smaller diameter than the interior of the enclosing sleeve 26. Thewasher 32 is made of a metal whose melting point is lower than thehighest permissible vulcanizing temperature of the elastomeric bondingelement 18.

In assembling the parts of the joint, prior to the vulcanizing process,each end of the pin 28 is inserted into a coupling member, so that thewasher 32 protrudes between them and beyond their outer circumference.

The beveled end surfaces 14 and 16 form annular V-pockets. The sleevecover is iitted in place, and an unvulcanized elastomeric moldablesubstance is molded into and around the joint, lling the V-pockets, andpressed to form the concave surfaces 20 and 22.

The joint is now vulcanized, to harden and season the bonding element18. The initial temperature is lower than the melting point of the metalof the washer 32. This permits partial curing of the elastomericmaterial 18, sucient to hold its shape.

When the vulcanizing process is partially completed, the pin 28 isdriven through the members 10 and 12 to shear the inner edge of theinsert. The assembly is then heated above the melting point of theinsert 32, and the melted metal of the Washer is drained out. Theresulting product is the completed joint shown in FIGURE 3. The cavityformed in the bonding element, together with the beveled end surfaces 14and 16 and the depressions 26 and 22, allows extensive flexing of thejoint, and there is suicient reinforcement to render the joint extremelydurable. For some types of elastomeric materials, a form is used to holdthe material in place until it solidiiies sutiiciently to hold itsshape.

The elastomeric material may consist of rubber, synthetic rubber such asneoprene, Buna, et cetera, or it may consist of any other suitableplastic material having the proper elastomeric properties and bondableto the metallic parts, either directly or through the use of suitablebonding material.

In the modification sho-Wn in FIGURE 4, a pair of coupling members 34and 36 are secured together in the same manner described above inconnection with the form shown in FIGURES 1-4 inclusive. A vulcanizablebonding member is molded about the ends of the couplings, and inside asleeve member 40. A cavity 42 is formed in the bonding member as before.Positive alignment is added to the joint by the addition of a ballbearing member 44 which is inserted into the joint and is retained by apair of yieldable or flexible packing members 46. These, in turn areheld in place, each by a spring ring 4S, which is sprung into and heldin place by an annular groove formed in the interior surface of eachcoupling member. This gives proper alignment and a limited movementunder compression to a joint where compressing movement is to beresisted.

The packing members 46 are provided with concave surfaces engaging theball member 44, The packing member may be made from nylon or any othersuitable material.

Although the preferred embodiment of the device has been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode of operation, which generallystated consist in a device capable of carrying out the objects setforth, as disclosed and deiined in the appended claims.

Having thus described my invention, 1 claim:

l. The method of making a universal joint which comprises the steps ofproviding an annular groove midway of the ends of a pin, casting awasher of low melting point alloy on said pin with a portion thereofseated in said groove, inserting each end of said pin into the adjacenthollow end of a coupling member, placing a sleeve member about saidwasher, molding a vulcanizable bonding element into said sleeve member,about said washer, and about the adjacent ends of said coupling members,vulcanizing said bonding element suciently to hold the shape thereof ata temperature below the melting point of the alloy of said washer,forcing said pin out of said coupling members and simultaneouslyshearing the portion' of said washer seated in said groove from the bodyof said washer, then subjecting said jo-int to a higher temperaturesufficient to melt said washer and draining away the molten materialthus forming an annular cavity in the Ibonding element. t

2. The method of forming an elastomeric element having a cavity and anenlargement of said cavity within the body thereof, which methodcomprises the steps of providing a lrst elongate insert having asubstantially uniform cross-sectional shape for forming said cavity,said rst insert having a melting point exceeding the curing Vtemperatureof said elastomeric element, mounting a second insert about a transversegroove in said first insert for forming lthe enlargement of said cavity,a portion of said second insert being seated in said groove, said secondinsert jhaving a melting point in the range of the curing temperature ofsaid elastomeric element, molding uncured elastomeric material aboutsaid second insert to form said elastomeric element,-there being aportion of said first insert projecting outside said elastomericelement, partially curing the elastomeric element at a temperature belowthe melting point of said inserts, sliding said rst insert from saidsecond insert and the partially cured elastomeric element in a directiontransverse to said groove so as lto shear the portion of said secondinsert seated in said groove, iinal curing said elastomeric element at atemperature exceeding the melting point of said second insert, anddraining the molten material of said second insert from the finallycured elastomeric element.

3. The method of making a bonded universal joint which comprises castinga low melting point annular insert about an annular groove located in apin intermediate its ends, inserting the opposite ends of said pin intoadjacently positioned hollow end portions of a pair of coupling members,placing a sleeve about the joint asformed, molding uncured elastomericmaterial into said sleeve about said annular insert and about the endsof said coupling members, submitting the joint as formed to a partialcuring process at a ltemperature below the melting point of said annularinsert, removing said pin from said annular insert, thereby shearing theportion of said insert seated in said annular groove, and iinal curingthe elastomeric material at a temperature exceeding the melting point ofsaid annular insert permitting lthe annular insert to melt and flow outof the joint.

4. The method of forming a cavity in a molded element of curableelastomeric material comprising the steps of forming an insert havingthe shape of the cavity to be formed, said insert comprising a bodyof-low melting alloy and a pin anchored to said body, said pin beinginseparable from said body except by shearing a portion of said body,molding the elastomeric element, Wlhile uncured, about said insert, saidpin extending outside said molded element, applying heat to the moldedelement -to at least partially cure same at a temperature below themelting temperature of said alloy to fix the shape of the molded elementwhile. said insert remains substantially rigid, removing said pin fromthe -body of said insert thus shearing a portion of said body, removalof said pin providing a passageway from the sheared portion of said bodyto the exterior of said molded element, thereafter heating said moldedelement to -a temperature exceeding the melting temperature of saidalloy to melt said body while `further curing said molded element, anddraining the molten ma# terial of said body from the molded elementthrough the passageway created by removal of said pin.

t References Cited in the ile of this patent UNITED STATES PATENTS17,599,924 Sanborn Sept. 14, 1926 2,251,804 Reuter et al Aug. 5, 19412,444,904 Worley A l July 6, 1948

